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Gemella morbillorum is a gram-positive coccus that is part of the normal microbiota of the human oral cavity and gastrointestinal tract. It is an opportunistic pathogen that can cause invasive infections, including septic arthritis. Septic arthritis caused by Gemella morbillorum is relatively rare, but when it occurs, it can lead to severe joint damage and other complications if not promptly diagnosed and treated. Here, we report a case of recurrent septic arthritis caused by Gemella morbillorum., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: We have obtained written informed consent from the patient for the publication of the report and accompanying images. And all authors agreed to publish. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

BACKGROUND This case report describes a case of a 25-year-old man who underwent a surgical procedure and was subsequently diagnosed with acute myeloid leukemia. Following his immediate admission to a specialized hospital unit for hematology and hemotherapy to receive chemotherapy, he was found to have a concurrent infection with multidrug-resistant Elizabethkingia meningoseptica as well as Enterococcus faecium. Both isolates are commonly associated with healthcare-associated infections. CASE REPORT The patient described in this report underwent an exploratory laparotomy, which is an invasive surgical procedure, and was subsequently diagnosed with acute myeloid leukemia following a biopsy. Chemotherapy was initiated immediately, during which the patient developed clinical signs and symptoms of infection. Blood cultures revealed the presence of Enterococcus faecium, while urine cultures identified Elizabethkingia meningoseptica. The VITEK-2 antibiogram for both bacteria revealed a multidrug resistance profile. E-test performed for glycopeptides indicated high-level resistance, with a minimum inhibitory concentration (MIC) exceeding 256 µg/mL. Prophylactic antibiotic therapy was initiated and subsequently adjusted according to the culture and antibiogram results. CONCLUSIONS Use of proper aseptic techniques during medical procedures is essential. Patients with severely compromised immunity undergoing numerous procedures require strict isolation measures to prevent infections, which can make the difference between life and death. Early laboratory identification of pathogenic clones and their antimicrobial resistance profiles is crucial for timely etiological diagnosis. This helps prevent the spread of infections and hospital infection outbreaks.

Background: Cutibacterium acnes(C. acnes), a Gram-positive anaerobe and a dominant bacterium species in the sebaceous follicles of the face was detected in the brain of Alzheimer's disease (AD) patients. It has been found that C. acnes activates non-specifically the innate immune system by producing proinflammatory cytokines and can participate in brain inflammation. We hypothesise that C. acnes could influence the brain through the structural alteration in axons and dendrites of neurons., Methods: In this regard, the hippocampus of rats was infected with C. acnes, and memory retention, amyloid-β (Aβ 1-42 ) deposition, hyperphosphorylated tau protein (p-Tau) formation, and expression levels of MAP2 and β-tubulin proteins in the hippocampus tissues were investigated., Results: C. acnes-infected rats displayed memory deficits and Aβ 1-42 deposits were detected in their hippocampus tissue up to 7 days post-infection. C. acnes was neurotoxic and exerted detrimental effects on MAP2 and β-tubulin proteins, which are required for normal neuronal function. An elevated level of p-Tau was also identified in infected animals., Conclusion: Based on these results, we propose that C. acnes infection of the brain participates in the initiation of the pathogenesis of sporadic AD through degeneration of axons and dendrites., Competing Interests: Declarations. Ethics approval: All methods were performed in accordance with the relevant guidelines and regulations )IR.SBMU.AEC.1401.022(. Consent for publication: Not applicable. Competing interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© 2024. The Author(s).)

Bacillus cereus , a global threat, is one of the major causes of toxin-induced foodborne diseases. However, a comprehensive assessment of the prevalence and characteristics of B. cereus worldwide is still lacking. Here, we applied whole-genome sequence analysis to 191 B. cereus collected in Africa, America, Asia, Europe, and Oceania from the 1900s to 2022, finding that CC142 dominated the global B. cereus clonal complex. The results provided direct evidence that B. cereus could spread through the food chain and intercontinentally. B. cereus from different generations worldwide showed coherence in the antibiotic-resistant gene and virulence and biofilm gene profiles, although with high genomic heterogeneity. The BCI-BCII-vanZF-fosB profiles and virulence and biofilm genes were detected at high rates, and we emphasized that B. cereus would pose a serious challenge to global public health and clinical treatment.IMPORTANCEThis study first emphasized the prevalence, genetic characteristics, and pathogenicity of Bacillus cereus worldwide from the 1900s to 2022 using whole-genome sequence analysis. The CC142 dominated the global Bacillus cereus clonal complex. Moreover, we revealed a close evolutionary relationship between the isolates from different sources. B. cereus isolates from different generations worldwide showed coherence in potential pathogenicity, although with high genomic heterogeneity. The BCI-BCII-vanZF-fosB profiles and virulence and biofilm genes were detected at high rates, and we emphasized that B. cereus would pose a serious challenge to global public health and clinical treatment., Competing Interests: The authors declare no conflict of interest.

Background: Gulosibacter massiliensis is a new species of gram-positive, short rod-shaped, aerobic, oxidase-negative, and catalase-positive bacteria, which was discovered in human peripheral blood and named recently in 2022. Currently, the clinical reports on G. massiliensis are limited, and its pathogenic ability and infectivity remain unclear., Case Presentation: We isolated G. massiliensis from the exudate of an emergency traumatic wound of the right foot of a 54-year-old man. The patient stepped into a gutter with the right foot, causing a wound with exposed bone, oozing blood, and local infection. Through timely surgical treatment and active debridement and nursing, the wound healed smoothly, and the patient was discharged from the hospital uneventfully. This strain could not be accurately identified using conventional biochemical reactions or matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis in our clinical laboratory. Finally, the strain was identified correctly using 16 S ribosomal RNA gene sequencing and historical data of Gulosibacter spp., and its drug susceptibility results were reported., Conclusion: Reports on clinical infection or isolation of G. massiliensis are limited. This is the first study reporting its isolation from wound secretions. It is a rare opportunistic infectious bacterium. Further clinical research will help us understand its infectivity and pathogenicity. This report could guide the treatment and laboratory detection of local wound infections caused by G. massiliensis., Competing Interests: Declarations Ethics approval and consent to participate Ethics approval was not applicable. Consent for publication Written informed consent was obtained from the patient for the publication of his case. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Enterococcus faecalis and Enterococcus faecium are frequent causes of healthcare-associated infections. Antimicrobial-resistant enterococci pose a serious public health threat, particularly vancomycin-resistant enterococci (VRE), for which treatment options are limited. The Centers for Disease Control and Prevention's Division of Healthcare Quality Promotion Sentinel Surveillance system conducted surveillance from 2018 to 2019 to evaluate antimicrobial susceptibility profiles and molecular epidemiology of 205 E. faecalis and 180 E. faecium clinical isolates collected from nine geographically diverse sites in the United States. Whole genome sequencing revealed diverse genetic lineages, with no single sequence type accounting for more than 15% of E. faecalis or E. faecium . Phylogenetic analysis distinguished E. faecium from 19 E. lactis (previously known as E. faecium clade B). Resistance to vancomycin was 78.3% among E. faecium , 7.8% among E. faecalis , and did not occur among E. lactis isolates. Resistance to daptomycin and linezolid was rare: E. faecium (5.6%, 0.6%, respectively), E. faecalis (2%, 2%), and E. lactis (5.3%, 0%). All VRE harbored the vanA gene. Three of the seven isolates that were not susceptible to linezolid harbored optrA , one chromosomally located and two on linear plasmids that shared a conserved backbone with other multidrug-resistant conjugative linear plasmids. One of these isolates contained optrA and vanA co-localized on the linear plasmid. By screening all enterococci, 20% of E. faecium were predicted to harbor linear plasmids, whereas none were predicted among E. faecalis or E. lactis . Continued surveillance is needed to assess the future emergence and spread of antimicrobial resistance by linear plasmids and other mechanisms.IMPORTANCEThis work confirms prior reports of E. faecium showing higher levels of resistance to more antibiotics than E. faecalis and identifies that diverse sequence types are contributing to enterococcal infections in the United States. All VRE harbored the vanA gene. We present the first report of the linezolid resistance gene optrA on linear plasmids in the United States, one of which co-carried a vanA cassette. Additional studies integrating epidemiological, antimicrobial susceptibility, and genomic methods to characterize mechanisms of resistance, including the role of linear plasmids, will be critical to understanding the changing landscape of enterococci in the United States., Competing Interests: The authors declare no conflict of interest.

Cutibacterium acnes is a major skin commensal that may act as an opportunistic pathogen. It is difficult to interpret findings of C. acnes in tissue cultures obtained during arthroplasty revision surgery, since they may represent true infection or contamination. This study investigated whether C. acnes obtained from prosthetic joint infections (PJIs) were related and shared common genomic traits that might correlate with clinical courses and patient outcomes. C. acnes isolates from revision surgery of patients with PJIs of the hip, shoulder, and knee were characterized using molecular methods to determine the sequence type (ST) and the presence of possible virulence determinants (Christie-Atkins-Munch-Peterson factors, dermatan sulfate-binding adhesion 1, hyaluronidase lyase, and linear plasmid). A standardized review of the patients' medical charts was performed. The study included 37 patients with C. acnes culture-positive tissue samples where multiple isolates of C. acnes belonged to the same ST. Most of the isolates belonged to phylotype IA 1 . Phylogenetic analysis of virulence determinants revealed no shared pattern among PJI isolates. Seven patients had a polymicrobial infection. Exchange revision was performed in 70% of the patients, and >50% of all patients received antibiotic treatment for ≥3 months. Failure was noted in seven patients. No specific ST or any identifiable unique feature among virulence determinants were found among C. acnes isolated from PJIs of hips and shoulders. The majority of patients had low inflammatory markers and were treated successfully, even polymicrobial infections. However, failure was more common among shoulder infections compared with hip infections., Importance: Prosthetic joint infection (PJI) is a rare complication after arthroplasty surgery. The infection seldom resolves without a combination of both surgical and antibiotic treatment and can cause significant suffering among affected patients. Cutibacterium acnes is a common skin bacterium that is most often found in shoulder PJIs but can also infect other prostheses. In this study, we conducted a review of patients with previously verified PJIs involving C. acnes in hip or shoulder prostheses, along with a genomic analysis of the bacteria causing the infections. The majority of patients had successful outcomes. We did not identify any specific phylogenetic lineage or specific molecular signature of virulence factors among these PJI-associated C. acnes isolates that seemed to be associated with increased potential to cause infection among this species. This indicates that C. acnes isolated from PJIs originates from the patients' own skin microbiome and is inoculated during the arthroplasty surgery., Competing Interests: B.S. has been a member of an advisory board at ADVANZ PHARMA, and has also received speaker’s fees from Correvio Pharma Corp and ADVANZ PHARMA. All other authors have none to declare.

Pyogenic spondylodiscitis is an uncommon but important clinical condition that often requires medical and/or surgical management. We report a case of spondylodiscitis caused by a rare pathogen, Gemella morbillorum. To date, worldwide, only six such cases of confirmed spondylodiscitis infection with this rare pathogen have been documented, and this is the first reported case in South Africa. The patient was a 55-year-old female who presented to us with a 1-month history of severe back pain radiating to her left leg. She reported to us that she visited the dentist around the time of onset of the symptoms. A workup showed raised inflammatory markers, and a positron emission tomography scan indicated features of discitis at level L2/L3. Tissue cultures from a biopsy identified G. morbillorum species infection, and she was treated successfully with antibiotics for 6 weeks. It is important to have a high index of suspicion when a patient has a history of dental work, and to rule out associated infection such as endocarditis. Treatment with culture-driven antibiotics yields good results.

Pyogenic spondylodiscitis is an uncommon but important clinical condition that often requires medical and/or surgical management. We report a case of spondylodiscitis caused by a rare pathogen, Gemella morbillorum. To date, worldwide, only six such cases of confirmed spondylodiscitis infection with this rare pathogen have been documented, and this is the first reported case in South Africa. The patient was a 55-year-old female who presented to us with a 1-month history of severe back pain radiating to her left leg. She reported to us that she visited the dentist around the time of onset of the symptoms. A workup showed raised inflammatory markers, and a positron emission tomography scan indicated features of discitis at level L2/L3. Tissue cultures from a biopsy identified G. morbillorum species infection, and she was treated successfully with antibiotics for 6 weeks. It is important to have a high index of suspicion when a patient has a history of dental work, and to rule out associated infection such as endocarditis. Treatment with culture-driven antibiotics yields good results.

Background: Vancomycin-resistant enterococci (VRE) represent a public health threat due to the few available treatments. Such alarm has triggered worldwide initiatives to develop effective antimicrobial compounds and novel delivery and therapeutic strategies. vanA operon is responsible for most cases of acquired vancomycin resistance in enterococci., Objectives: Development of a transcription factor decoy (TFD) system as a vanA gene transcription-inhibitor., Methods: Vancomycin MIC was determined in the presence of TFD-lipoplexes. Additionally, the effect of TFD-lipoplexes on the expression level of the vanA gene and the growth pattern of E. faecalis was evaluated. The haemolytic activity of the developed TFD-lipoplexes and their cytotoxicity were examined. TFD-lipoplexes efficiency in treating vancomycin-resistant E. faecalis (VREF) infection was tested in vivo using a systemic mice infection model., Results: A reduction in vancomycin MIC against VRE from 256 mg/L (resistant) to 16 mg/L (intermediate susceptible), in the presence of TFD-lipoplexes, was recorded. The developed TFD-lipoplexes lacked any effect on E. faecalis growth and significantly reduced the transcription level of the vanA gene by about 3-fold. In an initial evaluation of the safety of TFD-lipoplexes, they were found not to be overtly haemolytic to human blood or cytotoxic to human skin fibroblast cells. The co-administration of TFD-lipoplexes and vancomycin efficiently eradicated VREF infection in vivo., Conclusions: The developed TFD-lipoplexes successfully restored vancomycin activity against VREF. They offer a safe effective unconventional therapy against this stubborn organism and present a revolution in gene therapy that can be applied to other resistance-encoding genes in various organisms., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objectives: Clinical experience in the use of teicoplanin for treating enterococcal infective endocarditis (EIE) is scarce. The aim of this study was to describe the characteristics and outcomes of patients with EIE treated with teicoplanin monotherapy compared to standard therapy with ampicillin plus ceftriaxone., Methods: All consecutive adult patients diagnosed with EIE between January 2018 and September 2022 at a referral centre were reviewed. Characteristics of individuals treated with teicoplanin for ≥14 days [the treated with teicoplanin (TT) group] were compared with those who received ampicillin plus ceftriaxone (AC group)., Results: Sixty-six patients were included [61 (92%) E. faecalis infective endocarditis (IE) and 5 (8%) E. faecium IE]. Twenty-seven (41%) received teicoplanin: eight as first-line treatment and 19 as continuation therapy.The median duration of teicoplanin treatment was 30 (25-43) days. Surgery was indicated in 14/27 (52%) in the TT group and in 21/39 (54%) in the AC group, but was finally performed in 11/14 (79%) and 13/21 (62%) (P = 0.46), respectively. In-hospital mortality rate was 3/27 (11%) in the TT group and 12/39 (31%) in the AC group (P = 0.06). Patients treated with teicoplanin were more often discharged on outpatient parenteral antibiotic therapy [18/27 (67%) versus 6/39 (15%), P < 0.001] and median hospital stay was shorter [29 days (IQR 20-61) versus 50 days (IQR 43-68), P = 0.006]. One-year cumulative mortality was 8/27 (30%) in the TT group and 13/39 (33%) in the AC group (P = 0.46). There was one relapse in each group., Conclusion: Teicoplanin seems an effective treatment for selected patients with enterococcal IE, mainly to facilitate discharge., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The time of re-implantation of removed CIED for local infection or endocarditis has been debated because no randomized studies are available. Many authors prefer to delay reimplantation to the time of blood culture negative or clinical stability. In this case report we describe the case of E. faecalis CIED endocarditis treated with the combination ampicillin plus ceftobiprole and one-stage removal and re-implantation with early follow-up without relapse of infection. In case of E. faecalis infection, we hypothesize that ampicillin plus ceftobiprole combination might have bactericidal and anti-biofilm activity, therefore allowing one state re-implantation without relapse.

Eggerthella lenta is an obligate anaerobic, Gram-positive bacilli, belonging to the human microbiota of gastrointestinal and female reproductive tracts, oral cavity and prostate gland. In this article, we aim to describe clinical and microbiological characteristics of seven E. lenta strains causing bacteremia. We conducted a descriptive retrospective study including all E. lenta strains causing bacteremia, from February 2019 to August 2023 at the Basurto University Hospital. Seven patients were included in the study with a mean age of 72.7 years. Six patients presented risk factors associated with bacterial infections. All patients were admitted to the hospital because of suspicious of bloodstream infection associated with abdominal symptoms for intravenous antibiotic treatment. Four E. lenta isolates were resistant to penicillin, while all isolates presented high MICs to piperacillin/tazobactam and low MICs to amoxicillin/clavulanic acid. All patients recovered without no complications., (Copyright © 2024 Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. Published by Elsevier España, S.L.U. All rights reserved.)

Background/aim: Vancomycin-resistant Enterococcus causes significant morbidity, mortality, and excess healthcare costs when compared to vancomycin-susceptible isolates. Patients with hematological malignancies, especially those who undergo hematopoietic stem cell transplantation, are at a particularly high risk for infections with vancomycin-resistant Enterococcus, with mortality ranging from 40-100%. Linezolid and daptomycin are the two most commonly used antibiotics for treatment of vancomycin-resistant enterococcal infections, however, there has been recent emergence of resistance to these drugs as well., Case Report: We report the case of a 48-year-old male with hematological malignancy and graft failure post hematopoietic stem cell transplantation complicated by dialysis-dependent acute kidney injury and recurrent neutropenic fevers due to vancomycin-resistant Enterococcus faecium (VREf) bacteremia. Despite central line changes, and strict aseptic precautions, the bacteremia returned, showing resistance to daptomycin and linezolid after the second recurrence. As a final effort, using limited clinical data and in vitro studies, we utilized oritavancin off-label as salvage therapy for refractory VREf bacteremia, with subsequent clearance of blood cultures., Conclusion: This is a rare case of successful off-label use of oritavancin for recurrent multidrug-resistant VREf bacteremia in a patient with hematological malignancy after undergoing hematopoietic stem cell transplantation. It is important to increase awareness of the potential use of this novel antibiotic with increasing resistance of VREf to first-line agents., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

The purpose of this study was to establish a porcine model of urinary tract infection (UTI) with gram-positive uropathogens. Ten female domestic pigs were experimentally inoculated with human UTI isolates of Enterococcus faecalis (n = 3), Staphylococcus saprophyticus (n = 3), or Staphylococcus aureus (n = 4) and followed with regular urine samples. Bladders and kidneys were aseptically removed at termination (5-7 days post infection) and assessed by gross pathology and bacterial enumeration. Enterococcus faecalis (n = 3 of 3) and S. aureus (n = 2 of 4) successfully colonized the pig bladders. Inoculation with S. saprophyticus never resulted in detectable bacteriuria. All infected pigs had cleared the infection spontaneously before termination. Surprisingly, three (of four) pigs inoculated with S. aureus led to spontaneous infection with opportunistic pathogens. Also, one pig colonized with E. faecalis resulted in spontaneous infection with E. coli. In conlusion, the pig supports experimental UTI with E. faecalis for up to 24 h but not prolonged infection. S. aureus and S. saprophyticus fails to cause UTI in pigs and other animals should be considered for studying these pathogens., (© 2024 The Author(s). APMIS published by John Wiley & Sons Ltd on behalf of Scandinavian Societies for Pathology, Medical Microbiology and Immunology.)

Giant freshwater prawn (Macrobrachium rosenbergii (MR)) is a significant aquafarm species commercially cultured in Taiwan. Intensive farming practices have led to the outbreak of Lactococcus garvieae (LG), which causes Lactococcosis in MR. Recently, LG has re-emerged and the number of mortalities in prawn farms has increased in Taiwan. However, there is no preventative strategy described and a lack of knowledge on virulence factors and pathogenesis from LG in MR. The most virulent strain of L. garvieae from M. rosenbergii was screened in vivo among seven isolates selected for infectivity testing injecting 0.1 mL of 10 8  CFU/mL bacterial concentration. Among the seven isolates screened, L. garvieae 109-6 resulted in 100% mortality within 3 days post-infection. Furthermore, 109-6 L. garvieae LD 50 dosage from in MR was found to be 10 6  CFU/mL. Subsequently, the most virulent strain 109-6 was sequenced using MinIon Nanopore sequencing. Results indicated that the LG genome yielded a protein-coding of 3857 with 59 tRNA and 16 rRNA and no plasmid. Interestingly, the distribution of subsystems in the annotated genome revealed genes related to virulence, defence, and disease among LG 50 genes. Altogether, the virulent strain and its genome data revealed distinctive features of LG, which hinted toward its pathogenicity and could facilitate for better preventive strategies., (© 2024 John Wiley & Sons Ltd.)

Ocular surface inflammatory disorders, such as dry eye, are becoming increasingly prevalent. Developing new treatment strategies targeting harmful bacteria could provide significant therapeutic benefits. The purpose of this study was to characterize the common ocular pathogen Staphylococcus aureus and the rarer endophthalmitis-associated species Enterococcus faecalis isolated from the ocular surface of dry eye disease patients in Norway. Together the 7 isolates (5 S. aureus and 2 E. faecalis) comprise the complete set of members of each species isolated in our previous study of the ocular microbiome of 61 dry eye sufferers. We aimed to investigate the pathogenic potential of these isolates in relation to ocular surface health. To this end, we used whole genome sequencing, multiplex PCR directed at virulence genes and antibiotic susceptibility tests encompassing clinically relevant agents. The E. faecalis isolates showed resistance to only gentamicin. S. aureus isolates displayed susceptibility to most of the tested antibiotics, except for two isolates which showed resistance to trimethoprim/sulfamethoxazole and three isolates which were resistant to ampicillin. Susceptibilities included sensitivity to several first-line antibiotics for treatment of ocular infections by these species. Thus, treatment options would be available if required. However, spontaneous resistance development to gentamicin and rifampicin occurred in some S. aureus which could be a cause for concern. Whole genome sequencing of the isolates showed genome sizes ranging from 2.74 to 2.83 Mbp for S. aureus and 2.86 Mbp for E. faecalis, which is typical for these species. Multilocus sequence typing and phylogenetic comparisons with previously published genomes, did not suggest the presence of eye-specific clusters for either species. Genomic analysis indicated a high probability of pathogenicity among all isolates included in the study. Resistome analysis revealed the presence of the beta-lactamase blaZ gene in all S. aureus isolates and the dfrG gene in two of them; while E. faecalis isolates carried the lsa(A) gene which confers intrinsic resistance to lincosamides and streptogramin A in this species. Screening for virulence factors revealed the presence of various pathogenicity associated genes in both S. aureus and E. faecalis isolates. These included genes coding for toxin production and factors associated with evading the host immune system. Some of the identified genes (tst, hylA & hylB) are suggested to be linked to the pathophysiology of dry eye disease. Lastly, the presence of specific S. aureus virulence genes was confirmed through multiplex PCR analysis., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Enterococcus cecorum (EC) infection is an emerging endemic disease in UK and global broiler poultry with major economic impact and welfare concerns. There are significant research gaps with regards to EC pathogenesis, source of infection, transmission routes and early detection of disease, which this study aimed to address. In this prospective study, 725 environmental samples were collected from 4 broiler farms (A-D) the day before chick placement (d 1) and through the subsequent crop (d 7, 14, and 21). Cecal swabs were collected from birds that died of natural causes during the study period. A sample of birds that had been found dead or were culled for health reasons, were presented for post-mortem and samples were taken from lesions for EC culture. DNA was extracted from all environmental samples and EC detected using a qPCR and MALDI-TOF. Two EC isolates from diseased birds were inoculated on concrete slabs and incubated at 23°C and 32°C followed by swabbing of concrete culturing and determination of EC cfu at defined time points. Alongside environmental and bird sampling commercially available, smart camera systems were installed in selected houses on each farm to monitor bird activity and distribution. No EC outbreak occurred during the study, however, it was detected by qPCR in 215/725 (29.7 %) of all samples collected. Also, EC DNA was detected on average in 37% of samples collected on d 1, with approx. 88% of samples from chick paper being positive. Despite this, it was only cultured from 3 ceca samples and joint fluids of two infected birds from farm B on d 14 and 21. The survival experiments using isolates from infected chickens showed EC can survive on concrete for at least 21 d. This study provides invaluable insights into transmission pathways and tenacity of EC. Further studies are needed to determine strain characteristics in relation to their ability to cause disease and to further elucidate the sources of infection on poultry farms., Competing Interests: DISCLOSURES The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: To report the first case of acute Abiotrophia defectiva endophthalmitis post-keratoplasty and review the current literature., Methods: A 47-year-old male, post-keratoplasty, presented with vision loss and severe anterior chamber reaction. Diagnostic investigations included vitreous cultures and molecular analysis., Results: Abiotrophia defectiva was identified. Despite aggressive treatment, visual acuity remained low. We reviewed a total of 14 post-procedural cases of A. defectiva endophthalmitis, focusing on antibiotic and steroidal treatment regimens and long-term prognosis., Conclusion: We emphasize aggressive treatment of external disease prior to intraocular surgery. In cases of A. defectiva endophthalmitis, we advocate judicious use of steroids.

Enterococci are Gram-positive coccus bacteria that are normally present in the gastrointestinal tract and ordinarily function commensally with humans. Very few studies have investigated the characteristics of enterococcal infections. We aimed to characterize patients with urinary tract infections (UTIs) due to Enterococci and their outcomes. This was a retrospective cohort study between June 2012-November 2022. Patients who had clinically and microbiologically confirmed Enterococcal UTI based on a urine culture positive for E. faecalis or E. faecium with a count of ≥10 5  CFU/mL and having urinary tract symptoms were included. A total of 396 patients were eligible and included. The patients had a median age of 61 years and were mostly females (56.8 %). The most common characteristics were hospitalization in a non-ICU ward, having a urinary catheter, and recent use of antibiotics within the last 3 months (66.4 %, 59.3 %, and 51.8 %, respectively). Infection with E. faecalis was more common than E. faecium (77.3 % vs. 22.7 %). However, the latter exhibited higher rates of antibiotic resistance (P < 0.001 to several antibiotics) and was associated with significantly higher median C-reactive protein level (26.7 vs. 13 mg/dL; P = 0.025), mortality (23 % vs. 10.1 %; P = 0.002), and median length of stay (25 vs. 11.5 days; P < 0.001). We found that most patients with enterococcal UTIs had a history of having a urinary catheter and recent antibiotic use and were mostly females and hospitalized in non-ICU wards. E. faecium-infected patients experienced more severe episodes and poorer outcomes compared to patients infected with E. faecalis; thus, would need more aggressive therapy., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Detection of Helcococcus kunzii and Ignatzschineria ureiclastica / larvae has been made possible by recent advancements in microbiologic diagnostics. We report the first described case of polymicrobial bacteremia secondary to these two unique pathogens, and only the third case of I. ureiclastica / larvae bacteremia described in the United States. Myiasis has historically been thought of as an infestation. This case adds to the growing body of evidence that myiasis is potentially a vector for bacteria, and bacteremia, and the potential for the spread of other vector-borne diseases.

Purpose: Few data have been published on the efficacy of linezolid in enterococcal urinary tract infection (e-UTI). The aims of this study were to describe the characteristics of patients with enterococci UTI treated with linezolid, and to evaluate the efficacy and the tolerance of linezolid treatment., Methods: An observational multicentre retrospective study was conducted in 5 hospitals in France. Patients were included if they met the following criteria: ≥18 years, clinical and microbiological criteria for enterococcal UTI and linezolid treatment > 48 h. Primary outcome was clinical failure., Results: Eighty-one patients were included between January 2015 and December 2021. The median age was 73.0 [64; 83] years and 47 (58%) were men. The median Charlson comorbidity index was 3.00 [2; 6]. E. faecium was reported in 65 (80%) cases and E. faecalis in 26 cases (32%). Polymicrobial infections occurred in 41 (51%) cases. No enterococci was resistant to vancomycin. Before linezolid prescription an empiric antimicrobial treatment was started in 48 (59%) cases and was effective against enterococci in 19/48 (39.5%) patients for a median of 3.5 days [2.0; 4.0]. The median duration of linezolid antibiotic treatment was 13 days [10; 14]. Three adverse events were reported, none were serious but one led to discontinuation of treatment. Treatment failure was reported in 2 cases (2.5%)., Conclusion: This study provides evidence for efficacy and safety of linezolid in enterococcal UTI., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Osteoarthritis is a common cause of morbidity and mortality in geriatric gazelles. Propionibacterium australiense has been reported as a cause of systemic granulomas in cattle, but there are no descriptions of this bacteria infecting other species nor causing osteoarthritis, to our knowledge. An 8-y-old, castrated male, sand gazelle ( Gazella leptoceros leptoceros ) was managed for chronic, intermittent, progressive osteoarthritis of the right tarsus. Serial biopsies revealed pyogranulomatous dermatitis with intralesional bacteria. Serial diagnostic imaging identified osseous and soft tissue proliferation with draining tracts. Treatments over 1 y included broad-spectrum antibiotics, anti-inflammatories, joint debridement, and infusion with platelet-rich plasma and stem cells. Despite therapy, lameness persisted, azotemia developed, and subsequently, the animal was euthanized. On postmortem examination, the periarticular tissue of the right tarsus was markedly expanded by pyogranulomas and fibrosis. Histologically, the synovium, joint capsule, and overlying soft tissues were markedly expanded by pyogranulomas and numerous gram-positive and acid-fast-negative filamentous bacteria surrounded by Splendore-Hoeppli material. Within the joint, there was regionally extensive cartilage ulceration, osteonecrosis, osteolysis, and pannus formation. PCR assay of affected formalin-fixed, paraffin-embedded tissue amplified segments of 16S rRNA and β subunit of bacterial RNA polymerase ( rpoB ) genes with 99.7% and 95.6% identity to P. australiense . This bacterium should be considered a differential for chronic pyogranulomatous osteoarthritis in gazelles., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Urinary tract infections caused by Aerococcus urinae have rarely been reported in children, and the clinical characteristics remain unclear. We reviewed medical records of children whose urine cultures grew A. urinae (≥10 4  CFU/mL) at a tertiary children's hospital in Tokyo, Japan. We found 17 pediatric patients in a review of 22,769 urine cultures between June 2006 and May 2022. The median age of 17 patients was 10.7 years (IQR 8-13 years), and males represented 76.5 % of the patients. Sixteen patients (94.1 %) had underlying urological conditions (neurogenic bladder, vesicoureteral reflux, urethral stenosis, bladder exstrophy, or urinary catheterization). The chief symptoms were fever (35.3 %), malodorous urine (23.5 %), nausea (11.8 %), and back pain (5.9 %). Ten patients were asymptomatic. Pyelonephritis was diagnosed in five male patients. All of them had underlying abnormal conditions of the bladder, and two had malodorous urine. All patients had favorable outcomes after 10-14 days of ampicillin/amoxicillin-based antimicrobial therapy., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest associated with this manuscript., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Cutibacterium acnes, part of normal skin flora, is increasingly recognized as an opportunistic pathogen capable of causing chronic prosthetic joint infections (PJI) associated with total hip and knee arthroplasty. However, there is a paucity of literature examining the pathogenesis of C. acnes during PJI. To study this, we developed an implant-associated osteomyelitis murine model in which 8-10-week-old C57BL6 mice were subjected to transtibial implantation of titanium or stainless-steel L-shaped pins contaminated with C. acnes. Postsurgery, mice were killed on Days 14 and 28 for terminal assessments of (1) bacterial load in bone, implant, and internal organs (heart, spleen, kidney, and liver), (2) bone osteolysis (micro-CT), (3) abscess formation (histology), and (4) systematic electron microscopy (EM). In vitro scanning EM (SEM) confirmed that C. acnes can form biofilms on stainless-steel and titanium implants. In mice, C. acnes could persist for 28 days in the tibia. Also, we observed C. acnes dissemination to internal organs. C. acnes chronic osteomyelitis revealed markedly reduced bone osteolysis and abscess formation compared to Staphylococcus aureus infections. Importantly, transmission EM (TEM) investigation revealed the presence of C. acnes within canaliculi, demonstrating that C. acnes can invade the osteocyte lacuno-canalicular networks (OLCN) within bone. Our preliminary pilot study, for the first time, revealed that the OLCN in bone can be a reservoir for C. acnes and potentially provides a novel mechanism of why C. acnes chronic implant-associated bone infections are difficult to treat., (© 2024 Orthopaedic Research Society.)

Study Design: Animal laboratory study., Objective: This study investigated the effects of Cutibacteriumacnes and Staphylococcusepidermidis on the lumbar discs of rabbits, as well as the outcomes of combined infection., Summary of Background Data: Many studies have indicated that bacterial infections are associated with lumbar disc degeneration (LDD). The most commonly cultured bacteria from disc tissues are C. acnes and S. epidermidis ., Methods: New Zealand white rabbits (n=40) were randomly divided into control, C. acnes , S. epidermidis , and C. acnes plus S. epidermidis ( i.e. , combined) groups. All groups except the control were injected with 25 μL of saline at L4-L5 and 25 μL of bacteria (1×10 7 CFU/mL) at L5-L6. All injections were performed under x-ray guidance. Weight measurements, haematological evaluations, and magnetic resonance imaging were performed after 4, 8, and 12 weeks. Histological examination and gene expression detection were performed 12 weeks after surgery., Results: Inflammatory factors in the blood and weight did not differ among the groups after 4, 8, and 12 weeks ( P >0.05). However, after 4 weeks, LDD occurred in the C. acnes group, and discitis occurred in the S. epidermidis and combined groups, all of which worsened after 8 weeks. After 12 weeks, the nucleus pulposus (NP) protruded and compressed the spinal cord in the C. acnes group, and tissue staining showed decreased NP tissue and cartilaginous endplate fracture. In the S. epidermidis and combined groups, the discitis was more confined, but tissue staining revealed a significant decrease in NP tissue, and loss of the normal disc structure., Conclusions: In the early stage of infection in rabbits, C. acnes caused LDD, and S. epidermidis caused discitis. Coinfection with C. acnes and S. epidermidis caused discitis but was more limited in scope than infection with S. epidermidis alone., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Cutibacterium acnes is the bacterium most commonly responsible for shoulder periprosthetic joint infection (PJI) and is often cultured from samples obtained at the time of revision for failed shoulder arthroplasty. We sought to determine whether these bacteria originate from the patient or from exogenous sources. We also sought to identify which C. acnes genetic traits were associated with the development of shoulder PJI., Methods: We performed bacterial whole-genome sequencing of C. acnes from a single-institution repository of cultures obtained before or during primary and revision shoulder arthroplasty and correlated the molecular epidemiology and genetic content of strains with clinical features of infection., Results: A total of 341 isolates collected over a 4-year period from 88 patients were sequenced. C. acnes cultured from surgical specimens demonstrated significant similarity to the strains colonizing the skin of the same patient (P < .001). Infrequently, there was evidence of strains shared across unrelated patients, suggesting that exogenous sources of C. acnes culture-positivity were uncommon. Phylotypes IB and II were modestly associated with clinical features of PJI, but all phylotypes appeared inherently capable of causing disease. Chronic shoulder PJI was associated with the absence of common C. acnes genes involved in bacterial quorum-sensing (luxS, tqsA)., Conclusion: C. acnes strains cultured from deep intraoperative sources during revision shoulder arthroplasty demonstrate strong genetic similarity to the strains colonizing a patient's skin. Some phylotypes of C. acnes commonly colonizing human skin are modestly more virulent than others, but all phylotypes have a capacity for PJI. C. acnes cultured from cases of PJI commonly demonstrated genetic hallmarks associated with adaptation from acute to chronic phases of infection. This is the strongest evidence to date supporting the role of the patient's own, cutaneous C. acnes strains in the pathogenesis of shoulder arthroplasty infection. Our findings support the importance of further research focused on perioperative decolonization and management of endogenous bacteria that are likely to be introduced into the arthroplasty wound at the time of skin incision., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

The opportunistic pathogen Enterococcus faecium colonizes humans and a wide range of animals, endures numerous stresses, resists antibiotic treatment and stubbornly persists in clinical environments. The widespread application of antibiotics in hospitals and agriculture has contributed to the emergence of vancomycin-resistant E. faecium, which causes many hospital-acquired infections. In this Review, we explore recent discoveries about the evolutionary history, the environmental adaptation and the colonization and dissemination mechanisms of E. faecium and vancomycin-resistant E. faecium. These studies provide critical insights necessary for developing novel preventive and therapeutic approaches against vancomycin-resistant E. faecium and also reveal the intricate interrelationships between the environment, the microorganism and the host, providing knowledge that is broadly relevant to how antibiotic-resistant pathogens emerge and endure., (© 2024. Springer Nature Limited.)

Background:  Ventriculoperitoneal (VP) shunt infections are a fairly common complication in both the early and late postoperative periods. Sometimes diagnosis is difficult despite the fact that infection is often accompanied by clinical symptoms. Furthermore, pathogenic bacteria can be detected in the cerebrospinal fluid., Method:  We describe a case of chronic VP shunt infection in a 24-year-old female patient who was operated on for posterior fossa pilocytic astrocytoma and needed a VP shunt. The infection revealed itself 5 years after shunt implantation with nonspecific symptoms, and it took approximately 2 years to make a correct diagnosis. Meanwhile, the patient's condition became critical. The infection was caused by Propionibacterium acnes , which is capable of forming biofilms on implants, and which is difficult to identify due to the peculiarity of its cultivation., Result:  When the bacterium was identified, the shunt was replaced and antimicrobial therapy was performed, after which the patient's condition improved dramatically and she got back to her normal life., Conclusions:  This case shows how difficult the diagnosis of VP shunt infection can be and what clinical significance it can have for the patient., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Several single-center studies have suggested that eliminating isolation for vancomycin-resistant enterococci (VRE) control in the context of endemic or nonoutbreak settings, has no impact on infection rates. We performed a systematic review and meta-analysis on the impact of discontinuing isolation., Methods: We searched PubMed, Embase, the Cochrane Library, and Web of Science through April 10, 2024 for studies evaluating discontinuation of isolation for VRE. Subgroup analyses assessed sources of heterogeneity., Results: Nine studies were included in the final review. Four reported the incidence of hospital-acquired VRE (HA-VRE) infections and 5 reported the incidence of hospital-acquired VRE bloodstream infections (HA-VRE BSI). No significant difference between the rates of HA-VRE infection before and after stopping isolation was observed (risk ratios, 0.93; 95% confidence interval, 0.68-1.26; P = .62), as well as no significant difference on the incidence of HA-VRE BSI (risk ratios, 0.68; 95% confidence interval, 0.44-1.07, P = .09). Furthermore, we conducted 2 subgroup analyses: one stratified by whether the studies were conducted during Coronavirus Disease 19 (COVID-19), and the other stratified by whether clinicians continued to use personal protective equipment. Both analyses revealed no significant differences in the incidence of HA-VRE BSI and termination of isolation between the subgroups., Conclusions: In the context of endemic or nonoutbreak settings, discontinuation of isolation for VRE patients has not been associated with an increased rate of HA-VRE infections., (Copyright © 2024 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.)

Lactococcosis is a common bacterial fish disease caused by Lactococcus garvieae, L. petauri and L. formosensis. Although there are different PCR-based techniques to identify the etiological agent, none of these can differentiate these two bacteria without sequencing PCR-amplified fragments. In the present study, we developed a multiplex PCR assay for simultaneous detection and differentiation of L. garvieae and L. petauri. The specificity of the primers was validated against the bacterial DNA of the targeted and non-targeted bacteria. The sizes of the PCR amplicons were obtained as 204 bp for the DUF1430 domain-containing protein gene of L. garvieae, 465 bp for the Lichenan permease IIC component gene of L. petauri, and 302 bp for the teichoic acid biosynthesis protein F gene of both L. garvieae and L. petauri. The PCR amplicons were clearly separated by agarose gel electrophoresis. The multiplex PCR assay did not produce any amplification products with the DNA of the non-targeted bacteria. The multiplex PCR detection limits for L. garvieae and L. petauri were 5 and 4 CFU in pure culture and 50 and 40 CFU/g in spiked tissue samples, respectively. It takes less than 2 h from plate-cultured bacteria and 3 h from tissue samples to get results. In conclusion, the developed multiplex PCR assay is a rapid, specific, accurate, and cost-effective method for the detection and differentiation of L. garvieae and L. petauri and is suitable to be used for routine laboratory diagnosis of L. garvieae and L. petauri., (© 2024 The Author(s). Journal of Fish Diseases published by John Wiley & Sons Ltd.)

Enterococcus faecalis is considered a probiotic, commensal lactic acid bacterium in human breast milk (HBM), but there are circulating antibiotic resistant and virulence determinants that could pose a risk in some strains. The study aimed to conduct genomic analysis of E. faecalis isolates recovered from HBM and animal milk and to evaluate their probiotic and pathogenic features through comparative genomics with isolates from clinical specimens ( e.g ., urine, wound, and blood). Genomic analysis of 61 isolates was performed, including E. faecalis isolates recovered from HBM in Saudi Arabia. Genome sequencing was conducted using the MiSeq system. The fewest antibiotic resistance genes ( lsaA , tetM , ermB ) were identified in isolates from HBM and animal milk compared to clinical isolates. Several known and unknown mutations in the gyrA and parC genes were observed in clinical isolates. However, 11 virulence genes were commonly found in more than 95% of isolates, and 13 virulence genes were consistently present in the HBM isolates. Phylogenetically, the HBM isolates from China clustered with the probiotic reference strain Symbioflor 1, but all isolates from HBM and animal milk clustered separately from the clinical reference strain V583. Subsystem functions 188 of 263 were common in all analyzed genome assemblies. Regardless of the source of isolation, genes associated with carbohydrate metabolism, fatty acid, and vitamin biosynthesis were commonly found in E. faecalis isolates. In conclusion, comparative genomic analysis can help distinguish the probiotic or pathogenic potential of E. faecalis based on genomic features., Competing Interests: The authors declare there are no competing interests., (©2024 Badr et al.)

The presence of erm(T) gene conferring resistance to macrolides, lincosamides and streptogramin B (MLS B ), was screened in 296 enterococci collected from clinical samples in a central Italy hospital and seven Enterococcus faecium isolates resulted positive to erm(T) by PCR. All isolates were resistant to erythromycin, tetracycline, ciprofloxacin and ampicillin but susceptible to vancomycin and chloramphenicol. Whole Genome Sequencing analysis revealed that in five E. faecium isolates, all belonging to the sequence type ST80 included in the clonal complex CC17 responsible of nosocomial infections, erm (T) gene was chromosome-located, in different genetic contexts. In E. faecium 735,236, erm (T) was on a 4,159-bp region flanked by two IS1216 and inserted at the 3' end of the mp gene. In E. faecium 711,448 and 739,437, erm (T) was found in a 4,463-bp region identical to that detected in E. faecium 735,236 except for 319 bp. In E. faecium 713,729 and 757,415, erm (T) was on a 7,038-bp region flanked by IS1251 and ISEfm2 transposases and encompassed between the genes encoding a recombinase and three hypothetical proteins. erm(T)-carrying minicircles were detected in all isolates by inverse PCR assays demonstrating that erm(T) was included in mobile elements. However, in conjugation assays by filter mating, the erm(T) transferability was unsuccessful. Although macrolides are not used to treat enterococcal infections, the resistance is nonetheless widespread. These antibiotics are critically important in human medicine, but only few studies focused on erm (T)-harbouring clinical enterococci. The emergence of erm (T)-mediated erythromycin resistance among enterococci, potentially transferable to other nosocomial pathogens, should be constantly monitored., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The objective of this study was to establish a rapid visual diagnosis method for vancomycin-resistant Enterococcus faecium (VREFm) based on multienzyme isothermal rapid amplification (MIRA) combined with lateral flow strips (LFSs). The MIRA primers and probes were specifically designed to maintain the sequence of the VanA gene of VREFm. We optimized the reaction time and temperature and thoroughly assessed the specificity and sensitivity of the MIRA-LFS system. We also compared the MIRA-LFS method with the polymerase chain reaction (PCR) assay and the disc diffusion method. We then evaluated the MIRA-LFS assay for consistency testing and clinical application. The MIRA-LFS technique completed the amplification process within 30 min, and the results were observed on LFS. The method demonstrated high sensitivity, with a minimum detection limit of 1.066 CFU/µL for VREFm and exhibited specificity without cross-reactivity with other pathogenic bacteria. When applied to the detection of clinical samples, the method exhibited consistency with the PCR and agar dilution methods. The combined use of MIRA and LFS in this study facilitates simplifying the workflow for detecting VREFm, which is of great significance for rapidly detecting the enterococcal infections and preventing and controlling the nosocomial infections., Importance: One of the key approaches to treating and controlling vancomycin-resistant Enterococcus faecium (VREFm) is an accurate and rapid diagnosis. To achieve this goal, a simple and rapid method must be constructed for immediate detection in the field. Multienzyme isothermal rapid amplification (MIRA) is an isothermal rapid amplification method that allows amplification reactions to be completed under room temperature conditions. When combined with lateral flow strips (LFSs), MIRA-LFS enables the rapid detection of pathogenic microorganisms. However, the MIRA method often produces false signals. These false signals are eliminated by using base mismatches introduced in primers and probes. The MIRA-LFS system was constructed with high specificity and sensitivity for the detection of VREfm, without the limitation of sophisticated instruments. This enables the prompt formulation of diagnostic and therapeutic decisions., Competing Interests: The authors declare no conflict of interest.

Introduction: Cutibacterium acnes can both be a helpful colonizer of the human skin as well as the causative agent of acne and purulent infections. Until today, it is a moot point whether there are C. acnes strains exclusively devoted to be part of the skin microbiome and others, that carry special features enabling them to cause disease. So far, the search for the molecular background of such diverse behavior has led to inconsistent results., Methods: In the present study, we prospectively collected C. acnes strains from 27 infected persons and 18 healthy controls employing rigid selection criteria to ensure their role as infectious agent or colonizer. The genome sequences from these strains were obtained and carefully controlled for quality., Results: Deduced traditional phylotyping assigned almost all superficial isolates to type IA1, while the clinical strains were evenly distributed between types IA1, IB, and II. Single locus sequence typing (SLST) showed a predominance of A1 type for the control strains, whereas 56% of the clinical isolates belonged to types A1, H1 and K8. Pangenome analysis from all the present strains and 30 published genomes indicated the presence of an open pangenome. Except for three isolates, the colonizing strains clustered in clades separate from the majority of clinical strains, while 4 clinical strains clustered with the control strains. Identical results were obtained by a single nucleotide polymorphism (SNP) analysis. However, there were no significant differences in virulence gene contents in both groups., Discussion: Genome-wide association studies (GWAS) from both the pangenome and SNP data consistently showed genomic differences between both groups located in metabolic pathway and DNA repair genes. Thus, the different behavior of colonizing and infectious C. acnes strains could be due to special metabolic capacities or flexibilities rather than specific virulence traits., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Podbielski, Köller, Warnke, Barrantes and Kreikemeyer.)

Background: Micrococcus antarcticus (M. antarcticus) is an aerobic Gram-positive spherical actinobacterium that was initially isolated from Chinese Great-Wall station in Antarctica in 2000. M. antarcticus was considered to be of low pathogenicity, no previous cases of human infection by this organism have been reported. Here we describe the first report with community-acquired pneumonia (CAP) caused by M. antarcticus., Case Presentation: An 87-year-old female was presented to the Central Hospital of Wuhan in November 2023 with a chief complaint of cough, sputum production, and chest tightness for 2 weeks. Microbial culture of the patient's bronchoalveolar lavage fluid (BALF) and identification of the isolates using Matrix-assisted laser desorption ionization/time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing revealed M. antarcticus infection. Combined with clinical symptoms, laboratory and imaging examination, the patient was diagnosed with CAP. Then cefoperazone/sulbactam and levofloxacin was administrated, the patient's condition was improved and she was discharged after a week after admission, no abnormalities were detected during a 5-month follow-up., Conclusions: This case highlights that M. antarcticus, first identified from a patient with CAP, is an extremely rare pathogenic microorganism. Clinicians should be aware of its potential as a pathogen in the diagnosis and treatment of CAP., (© 2024. The Author(s).)

Background: One of the main risks of infection after hematopoietic stem cell transplantation (HSCT) is infection by gram-positive bacteria, including vancomycin-resistant enterococci (VRE). Based on the format of a global review and meta-analysis study, this study aims to investigate the incidence of VRE bloodstream infection (BSI) after HSCT in colonized individuals., Methods: The keywords of the systematic search included vancomycin-resistant enterococci and HSCT. These words were searched in Google Scholar, PubMed/Medline, Scopus, and Web of Science databases from January 1, 2000, to March 1, 2024. Studies that reported the prevalence of vancomycin-resistant enterococci in patients undergoing HSCT were included. The random effects model was used for the meta-analyses. Investigations were conducted according to PRISMA guidelines, and the protocol was registered in PROSPERO: CRD42024543491., Results: Out of 1100 screened papers, 28 were eligible. The random effects model was established to analyze the incidence of VRE BSI after HSCT. The pooled prevalence of co-infection for Allo-HSCT recipients was 3.023 (95% CI, Z-value = -3.5, p-value < 0.0001), and this value for Auto-HSCT recipients was 11.89 (95% CI, Z-value = -2.923, p-value < 0.001). These results showed that the rate of BSI due to vancomycin-resistant enterococcus in Auto-HSCT recipients is higher than Allo-HSCT., Conclusions: The prevalence of vancomycin-resistant enterococci in Auto-HSCT recipients is higher than that of Allo-HSCT, possibly due to colonization of the intestines of these people with vancomycin-resistant enterococci before transplantation. VRE Colonization before transplantation increases the likelihood of post-transplant VRE BSI and other bacterial infections, including Gram-negative. The strains should be analyzed by sequencing before and after HSCT for a more detailed investigation., (© 2024. The Author(s).)

Background: Alteration in the etiology of pediatric bloodstream infections (BSIs) and antimicrobial resistance (AMR) is not well known during the Coronavirus disease 2019 (COVID-19) pandemic. This study aimed to investigate the impact of the COVID-19 pandemic on pediatric BSIs and alteration in antimicrobial resistance phenotypes in Gram-positive bacteria., Methods: The frequency of BSIs among children under 18 years old was retrospectively recorded in a tertiary children's hospital in Tehran, Iran from February 2020 to December 2022. The status of COVID-19 infection using reverse transcription polymerase chain reaction, bacteremia/fungemia according to BACTEC 9120 Culture System results, characterization of bacteria using biochemical tests, and antimicrobial susceptibility patterns for Gram-positive bacterial isolates using disk diffusion method were determined. Statistical analysis was done to measure the correlation of COVID-19 infection with BSIs and AMR., Results: Out of 13,345 COVID-19 tests and 4,194 BACTEC blood culture requests, bacteremia/fungemia were confirmed in 10.37% (435/4,194) of the patients who requested both tests simultaneously. The COVID-19 infection was confirmed in 25.3% (110/435) of the patients with bacteremia/fungemia. The infection with characterized Gram-positive bacteria (GPB) and fungi was detected in 32.3% (140/433) and 8.31% (36/433) of the cases, respectively. Coagulase-negative Staphylococcus (CNS, 72, 16.62%), S. aureus (36, 8.3%), and Enterococcus spp. (22, 5%) were among the common isolates. Candida spp. and non-Candida yeasts were detected in 6.7% and 13.4% of the cases, respectively. A positive correlation was shown between the CNS bacteremia and COVID-19 infection (p-value = 0.019). Antibiotic susceptibility testing results showed the highest frequency of resistance to azithromycin among CNS, azithromycin and tetracycline among S. aureus and tetracycline among Enterococcus spp. Methicillin-resistance phenotype in the S. aureus (MRSA) and coagulase-negative Staphylococcus spp. (MR-CNS) was detected in 40% and 61.5% of the strains, respectively and the Enterococci were resistant to vancomycin in 33.3% of the isolates., Conclusion: A decline in the trend of BSIs by GPB and an increase in AMR was shown in children during the COVID-19 pandemic. Increasing antibiotic resistance is a concern; however, chloramphenicol, linezolid, and vancomycin remain active against common causes of GPB-BSIs., (© 2024. The Author(s).)

Background: The wide spread of antimicrobial resistance in Enterococcus faecalis is a critical global concern, leading to increasingly limited treatment options. The fsr quorum sensing (QS) plays a critical role in the pathogenicity of E. faecalis, allowing bacteria to coordinate gene expression and regulate many virulence factors. Therefore, fsr QS of E. faecalis represents a potential therapeutic target that provides an effective strategy to treat antibiotic-resistant infections induced by E. faecalis., Methods: In this study, distribution of different virulence factors including, gelatinase, protease, cell surface hydrophobicity and biofilm formation in sixty clinical isolates of Enterococcus faecalis was investigated. Sixty-six compounds were tested for their activity against fsr QS. The minimal inhibitory concentration of the tested compounds was evaluated using the microbroth dilution method. The effect of sub-inhibitory concentrations of the tested compounds on fsr QS was investigated using the gelatinase assay method. Additionally, the effect of potential QS inhibitor on the virulence factors was estimated. Quantitative real-time PCR was used to investigate the effect of the potential inhibitor on fsr QS related genes (fsrB-fsrC) and (gelE-sprE) and virulence associated genes including, asa1 and epbA., Results: The assessment of polidocanol activity against the fsr QS system was demonstrated by studying its effect on gelatinase production in E. faecalis clinical isolates. Sub-lethal concentrations of polidocanol showed a significant reduction in gelatinase and protease production by 54% to 70% and 64% to 85%, respectively. Additionally, it significantly reduced biofilm formation (P < 0.01) and interrupted mature biofilm at concentrations of ½, 1 × and 2 × MIC. Furthermore, polidocanol significantly decreased cell surface hydrophobicity (P < 0.01). Polidocanol at ½ MIC showed a significant reduction in the expression of QS genes including fsrB, fsrC, gelE and sprE by 57% to 97% without affecting bacterial viability. Moreover, it reduced the expression of virulence associated genes (asa1 and epbA) (P < 0.01)., Conclusion: Polidocanol appears to be a promising option for treating of E. faecalis infections by targeting the fsr QS system and exhibiting anti-biofilm activity., (© 2024. The Author(s).)

Background: Infections following shoulder surgery, particularly periprosthetic joint infection (PJI), are challenging to treat. Cutibacterium acnes is the causative pathogen in 39% to 76% of these cases. This study explores the efficacy of bacteriophage therapy as an alternative to conventional antibiotics for treating such infections., Methods: Nine phages with lytic activity were isolated from the skin of humans using C. acnes ATCC 6919 as the indicator host. These phages were tested individually or in combination to assess host range and antibiofilm activity against clinical strains of C. acnes associated with PJIs. The phage cocktail was optimized for broad-spectrum activity and tested in vitro against biofilms formed on titanium discs to mimic the prosthetic environment., Results: The isolated phages displayed lytic activity against a range of C. acnes clinical isolates. The phage cocktail significantly reduced the bacterial load of C. acnes strains 183, 184, and GG2A, as compared with untreated controls ( p < 0.05). Individual phages, particularly CaJIE7 and CaJIE3, also demonstrated significant reductions in bacterial load with respect to specific strains. Moreover, phages notably disrupted the biofilm structure and reduced biofilm biomass, confirming the potential of phage therapy in targeting biofilm-associated infections., Conclusions: Our preclinical findings support the potential of phage therapy as a viable adjunct to traditional antibiotics for treating C. acnes infections in orthopedic device-related infections. The ability of phages to disrupt biofilms may be particularly beneficial for managing infections associated with prosthetic implants.

Vancomycin-resistant enterococci (VRE) are a public health concern as they lead to therapeutic impasses and play a pivotal role in the dissemination of vancomycin resistance genes. As recent evidence suggests that wildlife can play a role in the dissemination of bacterial resistomes, this study explored the potential role of Algerian wild birds as a reservoir of VRE. A total of 222 cloacal and fecal samples were collected from various wild bird species and screened for VRE using a selective medium. Of the 47 isolated strains, 22 were identified as Enterococcus casseliflavus with the vanC2/C3 gene, 24 as Enterococcus gallinarum (19 carrying vanC1 and five carrying vanC2/C3), and one strain as Enterococcus faecalis with the vanC1 gene. Twenty-four (24) strains were multidrug-resistant with 61.7% resistant to rifampicin, while no resistance to teicoplanin, linezolid, and gentamicin was found. Additionally, 53.20% of the strains exhibited at least one virulence factor. To our knowledge, this study represents the first documentation of the vanC1 gene in E. faecalis isolated from wild birds. Furthermore, this gene was found to be carried by a conjugative plasmid, highlighting its ability to spread among bacterial populations and lead to the emergence of novel resistance phenotypes., (© The Author(s) 2024. Published by Oxford University Press on behalf of Applied Microbiology International.)

Background: Inflammation is a feature of coronary heart disease (CHD), but the role of proinflammatory microbial infection in CHD remains understudied., Methods and Results: CHD was defined in the MESA (Multi-Ethnic Study of Atherosclerosis) as myocardial infarction (251 participants), resuscitated arrest (2 participants), and CHD death (80 participants). We analyzed sequencing reads from 4421 MESA participants in the National Heart, Lung, and Blood Institute Trans-Omics for Precision Medicine program using the PathSeq workflow of the Genome Analysis Tool Kit and a 65-gigabase microbial reference. Paired reads aligning to 840 microbes were detected in >1% of participants. The association of the presence of microbe reads with incident CHD (follow-up, ~18 years) was examined. First, important variables were ascertained using a single regularized Cox proportional hazard model, examining change of risk as a function of presence of microbe with age, sex, education level, Life's Simple 7, and inflammation. For variables of importance, the hazard ratio (HR) was estimated in separate (unregularized) Cox proportional hazard models including the same covariates (significance threshold Bonferroni corrected P <6×10 -5 , 0.05/840). Reads from 2 microbes were significantly associated with CHD: Gemella morbillorum (HR, 3.14 [95% CI, 1.92-5.12]; P =4.86×10 -6 ) and Pseudomonas species NFACC19-2 (HR, 3.22 [95% CI, 2.03-5.41]; P =1.58×10 -6 )., Conclusions: Metagenomics of whole-genome sequence reads opens a possible frontier for detection of pathogens for chronic diseases. The association of G morbillorum and Pseudomonas species reads with CHD raises the possibilities that microbes may drive atherosclerotic inflammation and that treatments for specific pathogens may provide clinical utility for CHD reduction.

The aquaculture sector plays a vital role in global food security, yet it grapples with significant challenges posed by infectious diseases. Piscine lactococcosis is one of the significant threats in rainbow trout aquaculture due to its potential to cause severe economic losses through mortalities, reduced growth rates, and increased susceptibility to other pathogens. It poses challenges in disease management strategies, impacting the sustainability and profitability of rainbow trout farming. The current study focuses on the variations in serum blood parameters of farmed rainbow trout Oncorhynchus mykiss during a lactococcosis outbreak caused by Lactococcus garvieae. Blood samples were collected for biochemical analysis, fish were examined for parasites and bacteria, and DNA from bacterial colonies was PCR-amplified and sequenced for identification. Overall, 13 biochemical parameters, including proteins, enzymes, lipids, chemicals, and minerals, were measured in serum blood samples from both diseased and healthy fish. The results indicate significant alterations in the levels of these parameters during the outbreak, highlighting the impact of infections on the blood profile of farmed rainbow trout. Urea levels were significantly higher in diseased fish compared to controls, and creatinine, phosphorus, and magnesium also showed similar trends. Alanine aminotransferase and total protein levels were higher in control fish. Chloride levels differed significantly between groups. Iron levels were higher in controls and lower in diseased fish. No significant differences were found in other parameters. This study reveals significant changes in serum blood parameters of rainbow trout during a lactococcosis outbreak caused by L. garvieae. These changes highlight the potential of these parameters as tools for monitoring health status, stress, and aquaculture management. Continuous monitoring can provide valuable insights into disease severity and overall fish health, aiding in the development of improved management practices. The presented data contribute to understanding the pathophysiology of piscine lactococcosis and developing effective mitigation strategies for farmed rainbow trout., (© 2024 The Author(s). Journal of Fish Diseases published by John Wiley & Sons Ltd.)

With antimicrobial resistance (AMR) rapidly evolving in pathogens, quick and accurate identification of genetic determinants of phenotypic resistance is essential for improving surveillance, stewardship, and clinical mitigation. Machine learning (ML) models show promise for AMR prediction in diagnostics but require a deep understanding of internal processes to use effectively. Our study utilised AMR gene, pangenomic, and predicted plasmid features from 647 Enterococcus faecium and Enterococcus faecalis genomes across the One Health continuum, along with corresponding resistance phenotypes, to develop interpretive ML classifiers. Vancomycin resistance could be predicted with 99% accuracy with AMR gene features, 98% with pangenome features, and 96% with plasmid clusters. Top pangenome features overlapped with the resistance genes of the vanA operon, which are often laterally transmitted via plasmids. Doxycycline resistance prediction achieved approximately 92% accuracy with pangenome features, with the top feature being elements of Tn 916 conjugative transposon, a tet (M) carrier. Erythromycin resistance prediction models achieved about 90% accuracy, but top features were negatively correlated with resistance due to the confounding effect of population structure. This work demonstrates the importance of reviewing ML models' features to discern biological relevance even when achieving high-performance metrics. Our workflow offers the potential to propose hypotheses for experimental testing, enhancing the understanding of AMR mechanisms, which are crucial for combating the AMR crisis., Competing Interests: The authors declare no competing interests.

Background: Gram-positive bacteria are frequently resistant to empirical beta-lactams in febrile neutropenic patients with cancer. As microbiology and antibiotic susceptibility changes, we reevaluated the risk factors for resistant Gram-positive bacteremia in febrile neutropenic patients with cancer., Methods: Episodes of bacteremic febrile neutropenia in Seoul National University Hospital from July 2019 to June 2022 were reviewed. Resistant Gram-positive bacteria were defined as a pathogen susceptible only to glycopeptide or linezolid in vitro (e.g., methicillin-resistant staphylococci, penicillin-resistant viridans streptococci, and ampicillin-resistant enterococci). Episodes were compared to identify independent risk factors for resistant Gram-positive bacteremia., Results: Of 225 episodes, 78 (34.7%) involved resistant Gram-positive bacteremia. Multivariate analysis revealed that breakthrough bacteremia while being administered antibiotics (adjusted odds ratio [aOR], 6.794; 95% confidence interval [95% CI], 3.130-14.749; P < 0.001) and catheter-related infection (aOR 4.039, 95% CI 1.366-11.946; P = 0.012) were associated with resistant Gram-positive bacteremia. Chronic liver disease (aOR 0.231, 95% CI 0.059-0.905; P = 0.035) and hypotension at bacteremia (aOR 0.454, 95% CI 0.218-0.945; P = 0.035) were inversely associated with resistant Gram-positive bacteremia., Conclusions: Resistant Gram-positive bacteria should be considered in breakthrough bacteremia and catheter-related infection in febrile neutropenic patients with cancer., Competing Interests: Declaration of competing interest The authors have no relevant financial or non-financial interests to disclose., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Infections caused by vancomycin-resistant enterococci (VRE) are common. Real-time PCR assays targeting vanA and vanB facilitate screening of patients in healthcare settings to limit the risk of dissemination, especially amongst those at high-risk of infection or with limited treatment options. Such assays are commonly performed as reflex testing procedures where they augment phenotypic techniques and shorten turnaround time to benefit timely clinical management. 'Random access' and 'sample-to-result' real-time PCR platforms are suited for this application as they are of low complexity and less technically demanding. Modelled on these attributes, we configured a real-time PCR assay (VRE BD) for detection of vanA/B in clinical isolates of enterococci, adapted for the BD Max System (Becton Dickinson). We applied an unconventional approach by testing suspensions of microorganisms in water to circumvent the traditional pre-analytical genomic extraction process. Our objective of this study was to assess the performance of this assay for detection of VRE in cultures by validating against a traditional real-time PCR assay based on the LightCycler 2.0 platform (Roche, VRE RO). A high level of analytical sensitivity and specificity (≥99.0%) for both genes was obtained when testing suspensions derived from blood agar. Results for suspensions obtained from chromID VRE (Edwards Group) showed a similar level of performance for vanA detection (100%), but not for the vanB target (≥90.9%) where a lesser number of isolates were available for testing. However, our results for VRE detection in isolates from these media were repeatable and reproducible, and equated to positive and negative predictive values of ≥95.2% and ≥97.8%, respectively. Furthermore, the VRE BD assay was also able to accurately detect VRE in clinical and spiked BacT/ALERT (bioMérieux) blood cultures. Thus, the technical simplicity, short turnaround time and robustness of this high performing assay for VRE is suitable for reflex testing. In addition, the format developed for the BD Max platform has potential application for reflex testing other molecular targets of clinical importance., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: To analyse recent epidemiological trends of bloodstream infections (BSI) caused by Enterococcus spp. In adult patients admitted to tertiary care centres in Germany., Methods: Epidemiological data from the multicentre R-NET study was analysed. Patients presenting with E. faecium or E. faecalis in blood cultures in six German tertiary care university hospitals between October 2016 and June 2020 were prospectively evaluated. In vancomycin-resistant enterococci (VRE), the presence of vanA/vanB was confirmed via molecular methods., Results: In the 4-year study period, 3001 patients with BSI due to Enterococcus spp. were identified. E. faecium was detected in 1830 patients (61%) and E. faecalis in 1229 patients (41%). Most BSI occurred in (sub-) specialties of internal medicine. The pooled incidence density of enterococcal BSI increased significantly (4.0-4.5 cases per 10,000 patient days), which was primarily driven by VRE BSI (0.5 to 1.0 cases per 10,000 patient days). In 2020, the proportion of VRE BSI was > 12% in all study sites (range, 12.8-32.2%). Molecular detection of resistance in 363 VRE isolates showed a predominance of the vanB gene (77.1%)., Conclusion: This large multicentre study highlights an increase of BSI due to E. faecium, which was primarily driven by VRE. The high rates of hospital- and ICU-acquired VRE BSI point towards an important role of prior antibiotic exposure and invasive procedures as risk factors. Due to limited treatment options and high mortality rates of VRE BSI, the increasing incidence of VRE BSI is of major concern., (© 2024. The Author(s).)

Background Context: Reports of Cutibacterium acnes isolated in cultures of intervertebral disc samples suggest it as possibly responsible for inflammatory conditions causing Modic changes on spinal magnetic resonance imaging (MRI)., Purpose: Our objective was to investigate the prevalence of C. acnes in samples of intervertebral disc of patients with lumbar disc herniation; to investigate prognostic factors and the relationship of Modic changes with infection 1 year after microdiscectomy., Study Design: Prospective cohort study., Patient Sample: In this single-center study, patients consecutively operated on for disc herniation had samples of the disc, multifidus muscle and ligamentum flavum (as an indication of contamination) extracted for culture., Outcome Measures: Age, sex, alcohol and tobacco consumption, body mass index; function, pain, and Modic chances in MRI before surgery and MRI 1 year later; rate of disc, muscle and ligament infection (primary outcome); diabetes and corticoid use (confoundings)., Methods: The protruded disc, muscle and ligament samples were sent for culture analysis in up to 30 minutes. A subsample of 17 patients underwent next-generation sequencing (NGS) molecular analysis too. We performed descriptive analysis and comparison of groups of patients with and without infection or contamination using Student's t, Mann-Whitney, chi-square, or Fisher's exact tests as appropriate, and pre- and postsurgical comparisons with the Wilcoxon test., Results: From January 2018 to September 2019, 112 patients underwent open lumbar microdiscectomy, 67 (59.8%) men. Cultures showed 7 (6.3%) positive cases in the disc (2 with C. acnes), 3 (2.7%) in the ligament, and 12 (10, 7%) in muscle. No evidence of a difference in Modic alterations pre- or postoperatively was found between patients with and without positive culture 1 year after surgery. No association was found between culture positivity and functional or pain differences either. NGS results were all negative for C. acnes., Conclusions: We identified infective bacterial presence in the herniated disc in less than 2% of patients with disc herniation. C. acnes was not identified in any disc microbiome analysis. No significant association was observed between positivity for tissue infection and any clinical prognostic factor., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purposes: Enterococcal BSI is associated with significant morbidity and mortality, with fatality rates of approximately 20-30%. There are microbiological and clinical differences between E. faecalis and E. faecium infections. The aim of this study was to investigate differences in predisposing factors for E. faecalis and E. faecium BSI and to explore prognostic factors., Methods: This study was a post-hoc analysis of PROBAC, a Spanish prospective, multicenter, cohort in 2016-2017. Patients with E. faecalis or E. faecium BSI were eligible. Independent predictors for BSI development in polymicrobial and monomicrobial BSI and in-hospital mortality in the monomicrobial group were identified by logistic regression., Results: A total of 431 patients were included. Independent factors associated with E. faecium BSI were previous use of penicillins (aOR 1.99 (95% CI 1.20-3.32)) or carbapenems (2.35 (1.12-4.93)), hospital-acquired BSI (2.58 (1.61-4.12)), and biliary tract source (3.36 (1.84-6.13)), while congestive heart failure (0.51 (0.27-0.97)), cerebrovascular disease (0.45 (0.21-0.98)), and urinary tract source (0.49 (0.26-0.92)) were associated with E. faecalis BSI. Independent prognostic factors for in-hospital mortality in E. faecalis BSI were Charlson Comorbidity Index (1.27 (1.08-1.51)), SOFA score (1.47 (1.24-1.73)), age (1.06 (1.02-1.10)), and urinary/biliary source (0.29 (0.09-0.90)). For E. faecium BSI, only SOFA score (1.34 (1.14-1.58) was associated with in-hospital mortality., Conclusions: The factors associated with E. faecium and E. faecalis BSI are different. These variables may be helpful in the suspicion of one or other species for empiric therapeutic decisions and provide valuable information on prognosis., (© 2024. The Author(s).)

Introduction: Different initial manifestations of peritoneal dialysis-associated peritonitis (PDAP) may depend on the type of pathogenic organism. We investigated the association between the clinical characteristics of PDAP and susceptibility to vancomycin and investigated the possibility of using vancomycin monotherapy alone as an initial treatment regimen for some PDAP patients to avoid unnecessary antibiotic exposure and secondary infection., Methods: Patients with culture-positive PDAP were retrospectively analyzed and divided into two groups: peritonitis with only cloudy effluent (PDAP-cloudy) or with cloudy effluent, abdominal pain and/or fever (PDAP-multi). The bacterial culture of PD effluent and antibiotic sensitivity test results were compared between groups. Logistic regression was used to investigate factors predicting susceptibility to vancomycin., Results: Of 162 episodes of peritonitis which had a positive bacterial culture of PD fluid, 30 peritonitis were in the PDAP-cloudy group, and 132 peritonitis were in the PDAP-multi group. Thirty (100%) peritonitis in the PDAP-cloudy group had gram-positive bacterial infections, which was significantly greater than that in the PDAP-multi group (51.5%) (P < 0.001). Twenty-nine (96.7%) peritonitis in the PDAP-cloudy group were susceptible to vancomycin, compared to 67 (50.8%) in the PDAP-multi group (P < 0.001). The specificity of PDAP-cloudy for vancomycin-sensitive peritonitis was 98.48%. Only one patient (3.3%) in the PDAP-cloudy group experienced vancomycin-resistant peritonitis caused by Enterococcus gallinarum, which could neither be covered by vancomycin nor by the initial antibiotic regimen recommended by the current ISPD guidelines. The presence of only cloudy effluent was an independent predictor of susceptibility to vancomycin according to multivariate analysis (OR = 27.678, 95% CI 3.191-240.103, p = 0.003), in addition to PD effluent WBC counts (OR = 0.988, 95% CI 0.980-0.996, p = 0.004), diabetes mellitus (OR = 3.646, 95% CI 1.580-8.416, p = 0.002), first episode peritonitis (OR = 0.447, 95% CI 0.207-0.962, p = 0.039) and residual renal creatinine clearance (OR = 0.956, 95% CI 0.918-0.995, p = 0.027). Addition of these characteristics increased the AUC to 0.813 (95% CI 0.0.749-0.878, P < 0.001). The specificity of presenting with only cloudy effluent for vancomycin-sensitive peritonitis was 98.48%., Conclusions: Cloudy dialysate, as the only symptom at PDAP onset, was an independent predictor of vancomycin-sensitive PDAP, which is an important new insight that may guide the choice of initial antibiotic treatment., (© 2024. The Author(s).)